▎ 摘　　要

Annealing is well known technique to improve metal contacts. In order to anneal metal/graphene contacts information of suitable time of thermal treatment process is required, otherwise in a long annealing process undesired deformation in graphene layer or electronic device can be induced. In this article we introduce the investigation of the annealing time of metal/graphene structure. Electrical properties of contact between CVD grown graphene and metal (Au and Ni), using circular transmission line model (CTLM) contact geometry is observed. Raman spectroscopy is applied for characterization aiming to clarify surface and interface properties. It is found that the effective contact formation occur after 4 min annealing. The increase of thermal treatment time leads to unwished effects in graphene layers. (C) 2018 The Electrochemical Society.